What should be used to clean aluminum surfaces before GTAW?

Using a stainless steel brush to clean aluminum surfaces before Gas Tungsten Arc Welding (GTAW) is the most effective choice because it removes surface contaminants without introducing iron, which can lead to issues like contamination and poor weld quality. Stainless steel brushes are designed to effectively clean non-ferrous metals, such as aluminum, without imparting unwanted particles that may affect the weld integrity.

Aluminum is particularly susceptible to oxidation, and if not properly cleaned, the oxide layer can interfere with the welding process. The stainless steel brush, with its non-ferrous material, ensures that any residual oxidation, dirt, or oils are eliminated while maintaining the integrity of the aluminum surface.

Other cleaning methods, like using a steel wire brush, can introduce iron into the aluminum surface, leading to potential weld defects. Sandpaper can also be used, but it may not be as effective in removing all types of contaminants and could leave particles that might affect the weld. Using an acid solution requires careful handling and may not be necessary for most cleaning tasks, adding complexity that may not be justified for preparing aluminum.